Leptina, ghrelina e exercício físico
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Data
2007-02-01
Autores
Mota, Gustavo R. da [UNESP]
Zanesco, Angelina [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Endocrinologia e Metabologia
Resumo
A obesidade é atualmente um problema de saúde pública que provoca sérias conseqüências sociais, físicas e psicológicas. A etiologia da obesidade não é de fácil identificação, uma vez que a mesma é caracterizada como doença multifatorial de complexa interação entre fatores comportamentais, culturais, genéticos, fisiológicos e psicológicos. Recentes avanços na área de endocrinologia e metabolismo mostram que, diferentemente do que se acreditava há alguns anos, o adipócito sintetiza e libera diversas substâncias, não sendo apenas uma célula armazenadora de energia. Entre as substâncias liberadas pelo adipócito incluem-se a adiponectina, o fator de necrose tumoral-alfa, a interleucina-6 e a leptina. Especificamente, a leptina desempenha importante papel no controle da ingestão alimentar e no controle do peso corporal em mamíferos. Além disso, o hormônio ghrelina, recentemente descoberto, também parece influenciar o metabolismo energético e a obesidade. As alterações que o exercício físico provoca na fisiologia endócrino-metabólica podem contribuir sobremaneira para a prática clínica. Assim, essa revisão abordará os conhecimentos mais recentes sobre a leptina, a ghrelina e o papel dos diferentes tipos de exercício físico sobre estes hormônios. Os trabalhos mostram que a relação entre o exercício físico e a concentração plasmática desses peptídeos ainda não está clara. As razões para isso poderiam ser devidas aos diferentes protocolos de treinamento físico empregados nos estudos. Além disso, diferenças genéticas também podem explicar as discrepâncias entre os resultados obtidos em seres humanos, pois a existência de polimorfismo em alguns genes pode acarretar respostas celulares diferentes frente ao exercício físico.
Obesity is a major public health problem in the Western world resulting in serious social, physical and psychological damages. The genesis of obesity is complex involving a variety of factors such as genetic, psychological, metabolic and environmental factors. Progress in endocrinology and metabolism show that adipocyte is considered now as an endocrine tissue producing several substance including adiponectin, tumor necrosis factor-alpha, interleukin-6 and leptin. Specifically, leptin is the main peptide produced by the adipocyte and its serum concentration represents an important peripheral signal in the regulation of food intake and energy expenditure in mammals. In addition to leptin, a new peptide was discovered recently named ghrelin. Ghrelin, a peptide hormone identified in the stomach, is directly involved with the regulation of energy balance and obesity. Physical exercise has been used as a non-pharmacological tool in management of body weight and the effect of physical activity on weight control is an important issue for clinical studies in endocrinology field. Thus, this review will attempt to update the knowledge of leptin and ghrelin on the body weight regulation and the effect of exercise training on these peptide concentrations. It can be concluded that the relationship between physical exercise and the plasma concentration of these peptides is not clear. The reasons for that could be related to the differences in duration, intensity and frequency of the training program employed in each study. Indeed, most of the studies have not analyzed the intensity of training program by either plasma lactate concentration or maximum oxygen consumption. on the other hand, genetic basis could also explain the discrepancies found in some studies, since it has been shown that polymorphism for a variety of genes might be an important factor to determine the differences of cellular response to physical training.
Obesity is a major public health problem in the Western world resulting in serious social, physical and psychological damages. The genesis of obesity is complex involving a variety of factors such as genetic, psychological, metabolic and environmental factors. Progress in endocrinology and metabolism show that adipocyte is considered now as an endocrine tissue producing several substance including adiponectin, tumor necrosis factor-alpha, interleukin-6 and leptin. Specifically, leptin is the main peptide produced by the adipocyte and its serum concentration represents an important peripheral signal in the regulation of food intake and energy expenditure in mammals. In addition to leptin, a new peptide was discovered recently named ghrelin. Ghrelin, a peptide hormone identified in the stomach, is directly involved with the regulation of energy balance and obesity. Physical exercise has been used as a non-pharmacological tool in management of body weight and the effect of physical activity on weight control is an important issue for clinical studies in endocrinology field. Thus, this review will attempt to update the knowledge of leptin and ghrelin on the body weight regulation and the effect of exercise training on these peptide concentrations. It can be concluded that the relationship between physical exercise and the plasma concentration of these peptides is not clear. The reasons for that could be related to the differences in duration, intensity and frequency of the training program employed in each study. Indeed, most of the studies have not analyzed the intensity of training program by either plasma lactate concentration or maximum oxygen consumption. on the other hand, genetic basis could also explain the discrepancies found in some studies, since it has been shown that polymorphism for a variety of genes might be an important factor to determine the differences of cellular response to physical training.
Descrição
Palavras-chave
Exercício físico, Leptina, Ghrelina, Obesidade, Physical exercise, Leptin, Ghrelin, Obesity
Como citar
Arquivos Brasileiros de Endocrinologia & Metabologia. Sociedade Brasileira de Endocrinologia e Metabologia, v. 51, n. 1, p. 25-33, 2007.